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http://hdl.handle.net/2445/142059
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DC Field | Value | Language |
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dc.contributor.author | Zanin, Roberta | - |
dc.contributor.author | Fernández-Barral, Alba | - |
dc.contributor.author | Oña-Wilhelmi, Emma de | - |
dc.contributor.author | Aharonian, Felix | - |
dc.contributor.author | Blanch, Oscar | - |
dc.contributor.author | Bosch i Ramon, Valentí | - |
dc.contributor.author | Galindo Fernández, Daniel | - |
dc.date.accessioned | 2019-10-10T09:55:34Z | - |
dc.date.available | 2019-10-10T09:55:34Z | - |
dc.date.issued | 2016-11-29 | - |
dc.identifier.issn | 0004-6361 | - |
dc.identifier.uri | http://hdl.handle.net/2445/142059 | - |
dc.description.abstract | Aims. We probe the high-energy (>60 MeV) emission from the black hole X-ray binary system, Cygnus X-1, and investigate its origin. Methods. We analyzed 7.5 yr of data by Fermi-LAT with the latest Pass 8 software version. Results. We report the detection of a signal at ~8σ statistical significance that is spatially coincident with Cygnus X-1 and has a luminosity of 5.5 × 1033 erg s-1, above 60 MeV. The signal is correlated with the hard X-ray flux: the source is observed at high energies only during the hard X-ray spectral state, when the source is known to display persistent, relativistic radio-emitting jets. The energy spectrum, extending up to ~20 GeV without any sign of spectral break, is well fit by a power-law function with a photon index of 2.3 ± 0.2. There is a hint of orbital flux variability, with high-energy emission mostly coming around the superior conjunction. Conclusions. We detected GeV emission from Cygnus X-1 and probed that the emission is most likely associated with the relativistic jets. The evidence of flux orbital variability indicates the anisotropic inverse-Compton on stellar photons as the mechanism at work, thus constraining the emission region to a distance 1011-1013 cm from the black hole. | - |
dc.format.extent | 10 p. | - |
dc.format.mimetype | application/pdf | - |
dc.language.iso | eng | - |
dc.publisher | EDP Sciences | - |
dc.relation.isformatof | Reproducció del document publicat a: https://doi.org/10.1051/0004-6361/201628917 | - |
dc.relation.ispartof | Astronomy & Astrophysics, 2016, vol. 596, p. A55 | - |
dc.relation.uri | https://doi.org/10.1051/0004-6361/201628917 | - |
dc.rights | (c) The European Southern Observatory (ESO), 2016 | - |
dc.source | Articles publicats en revistes (Física Quàntica i Astrofísica) | - |
dc.subject.classification | Raigs gamma | - |
dc.subject.classification | Forats negres (Astronomia) | - |
dc.subject.other | Gamma rays | - |
dc.subject.other | Black holes (Astronomy) | - |
dc.title | Gamma rays detected from Cygnus X-1 with likely jet origin | - |
dc.type | info:eu-repo/semantics/article | - |
dc.type | info:eu-repo/semantics/publishedVersion | - |
dc.identifier.idgrec | 668416 | - |
dc.date.updated | 2019-10-10T09:55:35Z | - |
dc.rights.accessRights | info:eu-repo/semantics/openAccess | - |
Appears in Collections: | Articles publicats en revistes (Institut de Ciències del Cosmos (ICCUB)) Articles publicats en revistes (Física Quàntica i Astrofísica) |
Files in This Item:
File | Description | Size | Format | |
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668416.pdf | 1.68 MB | Adobe PDF | View/Open |
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